The Portage Park resident died Friday at Swedish Covenant Hospital of complications from an infection, said a friend, Juan Dies, co-founder of the Grammy-nominated group Sones de Mexico. Mr. Lopez was 77.

In some ways, Mr. Lopez’s life was a familiar rags-to-riches story. After he was born in Villahermosa in the state of Tabasco, his father left Mexico to work in the U.S. under the wartime Bracero — “strong arm” — program, which brought Mexican workers to the U.S. “He never saw his father again,” Dies said.

Struggling to raise four children on her own, young Gustavo’s mother sent him to live with an uncle in Matamoros.

At 8, “His uncle put him to work to earn his keep, so he would send him out to sell gum at the bars,” Dies said. “He doesn’t have good memories of that. He was not looked after. He was not loved there.”

He gravitated to two other kids who were hopping from bar to bar, singing with their dad. When their father stayed behind at a tavern, young Gustavo joined them and made it a trio, Dies said. He taught himself to play guitar by ear, perfected his harmonies, moved to Mexico City and co-founded Trio Los Angeles. That early group recorded eight singles under the direction of Ruben Fuentes of the famed Mariachi Vargas, and a critic ranked Mr. Lopez as one of the 11 best singers in Mexico.

Gustavo Lopez (right) in Los Tres Ases. He eventually relocated to Chicago, where he died on Friday. | Provided photo

In 1960, he landed an invitation to join the soaring voices of Juan Neri and Hector Gonzalez in Los Tres Ases, considered one of the “big four” bolero trios during the genre’s golden years. He was the baby-faced member, with hair that gleamed like starling feathers. The RCA Victor recording artists toured Mexico, Central America and the United States. He left the group in 1966.

Changing musical tastes — and his drinking — contributed to a downward spiral. He married multiple times and bounced around the U.S., according to friends and family.

He started working to maintain sobriety through Alcoholics Anonymous, often sharing his story with others who were struggling, they said. In the mid-80s, he resuscitated his career, performing in Detroit and Los Angeles. Stability deepened for him 20 years ago with a final, happy marriage to his fifth wife, Irma, said her daughter, Yari. In the mid-1990s, he moved to Chicago, where the bolero romantico style is more popular, she said. He performed with Jorge Jasso and Oscar Medina in Trio Los Duques, Dies said.

Mr. Lopez won a 2004 Illinois Arts Council fellowship for his contributions to music, said Dies, a show presenter at the Old Town School of Folk Music who built him a website and brought him to the school to perform.

“Music was his life,” Yari Lopez said.

He played weddings and worked as a strolling musician at the old La Hacienda del Sol, 1945 N. Sedgewick; La Margarita, 868 N. Wabash; La Finca, 3361 N. Elston; and at Su Casa, 49 E. Ontario, where he once entertained raw-boned Western actor Chuck Connors.

The patrons enjoyed him, but often, they didn’t recognize his caliber. “People never knew who they were listening to,” Dies said. Still, Mr. Lopez never frowned at playing “Macarena” and other novelty requests, he said. “What I admired about him is he said, ‘There’s nothing beneath me.’ He was always professional.”

“He was an amazing, amazing musician,” said Juan Castillo of Trio Los Primos de Mexico.

In one song, “Solo Tu,” he seems to be singing to a woman. But the lyrics then reveal another lifelong devotion. Roughly translated, he sings: “In the good, in the bad, in the sweet, and in the bitter, my dearest guitar, my wise guitar, my sweet guitar, it’s been you.”